Story highlights

No next of kin has come forward to claim the body

Footage that surfaced Monday appears to show moments before Kim's death

Kuala Lumpur, Malaysia (CNN)Kim Jong Nam didn't have a heart attack and the medics who conducted his autopsy found no obvious puncture marks or wounds, a top Malaysian health official said Tuesday, compounding the mystery over the North Korean's death.

Dr. Noor Hisham Abdullah, the director-general of Malaysia's Ministry of Health, addressed a packed room of journalists at the morgue where Kim's body is being held, saying that the cause of death won't be released until lab tests from the autopsy are completed.

Authorities in South Korea believe that Kim, the older, estranged half-brother of North Korean leader Kim Jong Un, was poisoned before he died on February 13. His death is being investigated as murder.

"Even if North Korea denies it, North Korean elites would 100% believe that the North is behind it, given how many executions have taken place so far under the North Korean regime," Thae said. "Even his uncle, Jang Sung Taek, was killed."

A South Korean think-tank affiliated with the country's intelligence agency (INSS) thinks at least 340 people have been ordered executed since Kim took power in December 2011.

Thae added that if Kim Jong Nam was killed under Kim Jong Un's orders, it would highlight the leader's paranoid state. "The existence of Kim Jong Nam is not really a threat to the North Korean regime," Thae said.

On Monday, security footage surfaced that appeared to show the assault on Kim Jong Nam shortly before his death.

When asked about reports that Kim had been poisoned, Abdullah reiterated that his department was waiting on lab results before making any conclusive statements.

Security footage from Fuji TV appears to show the moment Kim Jong Nam was attacked February 13.

Diplomatic fallout

Diplomatic relations between Malaysia and North Korea have been strained in recent days, culminating with Malaysia summoning Pyongyang's ambassador and recalling its representative to North Korea, according to a statement from Malaysia's Foreign Ministry.

The moves came after Pyongyang's ambassador, Kang Chol, accused Malaysia conspiring with "hostile forces" during the murder investigation.

He told reporters the investigation was being "politicized by Malaysia in collusion with South Korea."

But a Chinese official said the decision was simply a step towards enforcing existing UN sanctions.

"This is a move of China fulfilling relevant stipulations in Resolution 2321, honoring its international obligations and acting in accordance with Chinese laws and regulations," China's Foreign Ministry spokesperson, Geng Shuang, said in a press conference on Tuesday.

The suspects

Kim died February 13 at the Kuala Lumpur International Airport 2, where he was planning to catch a flight to the Chinese-controlled city of Macau.

He "felt like someone grabbed or held his face from behind" and then started to feel dizzy, according to Selangor State Criminal Investigations Department Chief Fadzil Ahmat.

An ambulance was eventually called to take him to the hospital, but he died en route.

So far, police have arrested four suspects and looking for four more who were believed to have left Malaysia the day of the attack.

One of the people in custody told police she thought she was participating in a gag for a television show.

The four who fled are North Korean, as is one of the four currently in Malaysian custody.

Interpol is assisting with the search for the suspects at large, each of who left Malaysia the day of Kim's death, Malaysian authorities believe.

When asked if North Korea had ordered his murder, a top Malaysian police official merely said, "the four (on the run) hold North Korean nationality, that is all."

CNN's Kocha Olarn reported from Kuala Lumpur, while Joshua Berlinger reported and wrote from Hong Kong. CNN's Saima Mohsin and journalists Sol Han and Salhan Ahmad contributed to this report.